Effect of secondary phase formation on the carbonation of olivine

Large-scale olivine carbonation has been proposed as a potential method for sequestering CO2 emissions. For in situ carbonation techniques, understanding the relationship between the formation of carbonate and other phases is important to predict the impact of possible passivating layers on the reaction. Therefore, we have conducted reactions of olivine with carbonated saline solutions in unstirred batch reactors. Altering the reaction conditions changed the Mg-carbonate morphology. We propose that this corresponded to changes in the ability of the system to precipitate hydromagnesite or magnesite. During high-temperature reactions (200 °C), an amorphous silicaenriched phase was precipitated that was transformed to lizardite as the reaction progressed. Hematite was also precipitated in the initial stages of these reactions but dissolved as the reaction proceeded. Comparison of the experimental observations with reaction models indicates that the reactions are governed by the interfacial fluid composition. The presence of a new Mgsilicate phase and the formation of secondary products at the olivine surface are likely to limit the extent of olivine to carbonate conversion. © 2010 American Chemical Society

Bawitius, gen. nov., a giant polypterid (Osteichthyes, Actinopterygii) from the Upper Cretaceous Bahariya Formation of Egypt

A newly discovered osteichthyan ectopterygoid from the Upper Cretaceous (lower Cenomanian) Bahariya Formation of the Bahariya Oasis, Egypt, is nearly identical to the holotypic specimen of Polypterus? bartheli from the same area and geologic unit. The Bahariya ectopterygoids are referable to Polypteridae based on the presence of a robust, laterally directed process that articulates with the maxilla. Additionally, ganoid scales from the Bahariya Formation have an isopedine layer, a histological character of Polypteriformes; but differ from those of previously described members of this clade in having a discontinuous ganoin layer, rectilinear shape, and proportionally small articular processes. Both the ectopterygoids and the scales are unusually large, and are the only polypteriform remains so far identified from the Bahariya Formation. The ectopterygoids and (tentatively) the scales are herein assigned to a single species of gigantic polypterid, the morphology of which is sufficiently distinctive to warrant its placement in a new genus, Bawitius, gen. nov. Differences in scale anatomy and the enormous disparity in body size between Bawitius and Serenoichthys support the hypothesis (originally proposed on the basis of varied fin spine morphologies) that a diversity of polypterid fishes inhabited North Africa during the early Late Cretaceous. © 2012 Copyright Taylor and Francis Group, LLC

On the forest front: labour relations and seasonal migration in 1960s–80s

Published online: 05 February 2018This article explores the shaping of seasonal labour migration practices in the region of Transcarpathia, acquired by the Soviet Union in the aftermath of the Second World War. In the analysis of migration from that region to the lumber camps of Western Siberia between the late 1950s and the 1970s, the article focuses on the interaction between the state's migration policies - which attempted to manage and stream labour mobility from the region - and the local migration initiatives that developed contrary to the state's aspirations and bypassed the state labour distribution agencies. I argue that the migrant workers' attitude to labour was the key to their outstanding productivity, to the building of longstanding relationships with managers, to the construction of the migrants' self-image and, indeed, to their identity. Situated in the general context of labour relations characteristic of the Soviet Union, the migrant workers' labour practices constituted an alternative to the overall functioning of the labour process in the USSR. Eventually, migrant workers came to represent a cultural paradox within the Soviet axiological system: the value of their labour performance could hardly be denied, but their acquisitive motives and their evading the official employment channels turned them into scapegoats rather than heroes of labour.